Digital Smile Designed Computer-Aided Surgery versus Traditional Workflow in "All on Four" Rehabilitations: A Randomized Clinical Trial with 4-Years Follow-Up.

The aim of the present study was to evaluate and compare the traditional "All on Four" technique with digital smile designed computer-aided "All on Four" rehabilitation; with a 4-years follow-up. The protocol was applied to a total of 50 patients randomly recruited and divided in two groups. Digital protocol allows for a completely virtual planning of the exact position of the fixtures, which allows one to perform a flapless surgery procedure with great accuracy (mini-invasive surgery) and also it is possible to use virtually planned prostheses realized with Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) (methods for an immediate loading of the implants. After 4 years from the treatments 98% of success were obtained for the group of patients treated with the traditional protocol and 100% for the digital protocol. At each time interval a significant difference in peri-implant crestal bone loss between the two groups was detected; with an average Marginal Bone Loss (MBL) at 4 years of 1.12 ± 0.26 mm in the traditional group and 0.83 ± 0.11 mm in the digital group. Patients belonging to the digital group have judged the immediate loading (92%), digital smile preview (93%), the mock-up test (98%) and guided surgery (94%) as very effective. All patients treated with a digital method reported lower values of during-surgery and post-surgery pain compared to patients rehabilitated using traditional treatment. In conclusion, the totally digital protocol described in the present study represents a valid therapeutic alternative to the traditional "All on Four" protocol for implant-supported rehabilitations of edentulous dental arches.

Virtual Implant Rehabilitation of the Severely Atrophic Maxilla: A Radiographic Study.

BACKGROUND: Advanced maxillary atrophy is one of the most common clinical scenarios where implant placement could become difficult. Nevertheless, a volumetric evaluation using a suitable diagnostic software could facilitate the implant planning. The purpose of the present study is to suggest the potential application of the maxillary retro-canine area as the designated location for virtual tilted implants. METHODS: A sample of Cone Beam Computed Tomography (CBCT) images from the Department of Dentistry (IRCSS San Raffaele, Milan, Italy) was evaluated. After a 3D anatomical evaluation, tilted implants were virtually positioned in the retro-canine regions. All the implants were inserted using the same procedure at 30° and 45° degrees of tilting. The length, palatal angulation and diameter of the placed implant were identified. RESULTS: A total of 220 tilted implants were placed. An average implant measurement of 13.51 mm in length and 3.42 mm in diameter were calculated. Additionally, an average buccal-palatal angulation of 6° was identified. Upon statistical analysis, the implant length was found to be significantly higher at 45° degrees of mesio-distal angulation than at 30° degrees (<0.0001). CONCLUSIONS: A considerable number of patients show a significant degree of bone atrophy. The implant-supported treatment plan can rely on three-dimensional imaging of the residual bone as a guiding tool to establish the most effective implant position for each specific case. In this study, it was found that an implant could have a greater length if its mesio-distal angulation was more accentuated. In addition, owing to the volumetric evaluation, it was possible to virtually insert tilted implants in almost all of the cases of atrophy. This could lead clinicians to consider the retro-canine area as a viable place to insert a longer tilted implant.